The present invention relates to active structural elements of aircraft. In particular, the present invention relates to a structural element for an aircraft, comprising an active element and a passive element, an aircraft comprising a corresponding structural element, the use of a structural element in an aircraft, and a method for the active structuring of aircraft.
In the fuselage of aeroplanes, floor structures that comprise transverse floor girders and seat rails are connected to the frame on the right and left by means of rivets and are in turn supported vertically downward by the frame by way of so-called Samer rods. In this arrangement the seat rails extend transversely over the transverse girders. The floor structures are closed off with the use of floor panels. This construction is designed to achieve as rigid a floor as possible.
Despite the stiffening described above, the entire fuselage structure is to be considered an elastic formation. As a result of gust loads and flight manoeuvres a host of different types of elastic deformation are introduced into the fuselage. The longer the fuselage the more frequent the occurrence of oscillations that can lead to a so-called fishtailing effect in which the rear of the fuselage oscillates to and fro. Oscillations in the fuselage affect passenger comfort. In addition, in very large floor structures there is the danger of the floor acting as an elastic structure.
In particular in the case of a large length/diameter ratio, further stiffening of fuselages quickly involves weight problems, i.e. further stiffening using more material clearly results in significant additional weight while providing relatively modest improvements in rigidity.
DE 102 26 241 A1 describes a method for suppressing elastic aircraft-fuselage movements. In this arrangement a sensor measuring system is used to register fuselage movements, and the elastic fuselage movements are subsequently suppressed by a mass system arranged in the aircraft.